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白口铸铁是一种重要的抵抗磨损的金属材料。其抗磨性决定于硬度,强度和韧性的综合性能指标因而与其组织组成物的结构,显微硬度,相对数量,分布及内聚强度都有密切的关系。铸态组织就是高显微硬度的碳化物孤立地分布在马氏体基体时较为理想,而合金化和变质处理的正确选用是最经济合理地获得理想组织的关键。 从我国资源出发,锰合金化是有前途的但为扬长避短,锰含量不宜过高,而为获得铸态马氏体组织应辅加铜、铬、钼、硼等多种合金元素。硼的加入可以提高锰白口铸铁的淬透性,碳化物的显微硬度和整体硬度。合适的硼加入量既可得到上述效果而又不降低韧性。硼在镍铬白口铸铁中也可以提高碳化物的显微硬度。硼的加入使白口铸铁中碳化物的数量增多。 采用包内变质处理的方法而不用高合金化的方法改变碳化物的分布,经济合理而且简便可行。稀土变质处理能使碳化物成为紧实的板块状而不是成为粗的网状聚合物,使韧性显著提高(α_k=0.8公斤-米/厘米~2)。硼的加入能使碳化物成为方块形。但如何控制工艺参数保证获得应有的变质效应的试验研究工作还需继续。
White cast iron is an important wear-resistant metal material. Its wear resistance is determined by the comprehensive performance index of hardness, strength and toughness and thus has close relation with the structure, microhardness, relative quantity, distribution and cohesive strength of its tissue composition. As-cast microstructure is the high microhardness carbide isolated in the martensite matrix is ideal, and the correct selection of alloying and metamorphic is the most economical and reasonable to obtain the ideal organization of the key. Starting from our resources, manganese alloy is promising, but to avoid weaknesses, the manganese content should not be too high, and to obtain as-cast martensite should be supplemented with copper, chromium, molybdenum, boron and other alloying elements. Boron can increase the hardenability of manganese white cast iron, carbide microhardness and overall hardness. The appropriate amount of boron is added to achieve the above effect without reducing the toughness. Boron in nickel-chromium white cast iron can also increase the microhardness of carbides. The addition of boron increased the amount of carbides in white cast iron. It is economical and reasonable to use the method of metamorphic treatment in the package to change the distribution of carbides instead of the high alloying method. Rare earth modification can make the carbide become a tight plate rather than become a coarse network polymer, the toughness was significantly improved (α_k = 0.8 kg - m / cm ~ 2). The addition of boron can make the carbides square. However, the experimental research on how to control the process parameters to obtain the proper metamorphic effect needs to be continued.